THE SMALL INTESTINE. 409 



abdomen. The ileum is more in the right lower quadrant of the abdomen. Accord- 

 ing to Treves, the intestine from six to eleven feet from its commencement has the 

 longest mesentery and is apt to be found in the pelvis. The lower end of the ileum 

 is also usually found in the pelvis, and rises over its brim to join the caecum. 



There is no certainty, however, of finding a definite piece of the small intestine 

 under any special point on the surface, because the varying distention and move- 

 ments cause frequent changes of position. 



Meckel's Diverticulum. In the embryo the vitello-intestinal duct passes 

 from the umbilicus to the lower end of the small in- 

 testine. Normally this disappears, but sometimes a 

 portion of it remains and there is found, one to three 

 feet above the ileocaecal valve, a finger-like projec- 

 tion from the side of the ileum, 5 to 7.5 cm. (2 to 

 3 in.) long. This is called MeckeV s diverticnlum, 

 and may become the site of disease the same as the 

 rest of the ileum. From its extremity a fibrous band 

 may run to the umbilicus. This has been in rare 

 instances the source of strangulation, causing intesti- 

 nal obstruction. One such case has been under our 

 care (Fig. 421). 



Peyer's patches (noduli lymphatic! aggre- 

 gati) are most numerous in the lower portion of the 

 ileum. They are ulcerated in typhoid cases and are 

 frequently the site of perforations. These patches 

 are from i to 2.5 cm. (^ to I in. ) wide and 2.5 to 

 7.5 cm. ( i to 3 in. ) long. When affected in typhoid Pl - 4ai -~~ M ^^.^ i ^^ 1 ) ttm< (From 

 fever they can readily be seen through the intestinal 



walls. By holding the intestine up against the light both Peyer's patches and the 

 valvulae conniventes can readily be seen. 



The perforations in typhoid fever occur usually within three feet of the ileo- 

 caecal valve, though occasionally they may occur, as we have seen, in the appendix, 

 or higher up in the small intestine, or even in the large intestine. 



OPERATIONS. 



The small intestines are frequently resected and anastomosed with themselves 

 or other portions of the gastro-intestinal canal. Gastro-enterostomy has been alluded 

 to on page 406. 



On opening the abdomen, if it is desired to find the upper end of the small 

 intestine, the omentum is pulled out, drawing with it on its under surface the 

 transverse colon. The hand is to be passed backward on the under surface of the 

 transverse mesocolon until the spine is reached; on its left side will be felt the duo- 

 denojejunal flexure. On drawing the jejunum to the right, the ligament of Treitz 

 will be seen. A loop 40 cm. (16 in.) down may be taken and brought up in front 

 of the omentum and used for an anterior gastro-enterostomy, or the intestine 

 immediately below the flexure may be used for a posterior gastro-enterostomy (see 

 page 406). If one desires to find the lower end of the small intestine, then a search 

 is made for the colon in the right iliac region. It is recognized by its longitudinal 

 bands and is followed down to the ileocaecal junction. If the case is one of typhoid 

 fever, a rapid examination is then made from the ileocsecal valve upward for perfora- 

 tions. It is desirable at times to determine which is the proximal and which the 

 distal end of an intestinal loop. The best way to do so is to follow the loop down 

 to the mesenteric attachment, as advised by Monks ; if the mesentery proceeds up 

 and to the left you have the proximal end; if, however, it is passing down to the 

 right you have the distal end. 



The intestine receives its nourishment from the mesentery and will die when 

 detached, hence it is necessary to avoid injury or detachment of the mesentery or 

 its vessels ; when this detachment has occurred the involved portion of intestine is 

 resected and removed. 



